A tooth cone beam computer tomography image segmentation method based on the local Gaussian distribution fitting / 生物医学工程学杂志

Oral teeth image segmentation plays an important role in teeth orthodontic surgery and implant surgery. As the tooth roots are often surrounded by the alveolar, the molar's structure is complex and the inner pulp chamber usually exists in tooth, it is easy to over-segment or lead to inner edges in teeth segmentation process. In order to further improve the segmentation accuracy, a segmentation algorithm based on local Gaussian distribution fitting and edge detection is proposed to solve the above problems. This algorithm combines the local pixels' variance and mean values, which improves the algorithm's robustness by incorporating the gradient information. In the experiment, the root is segmented precisely in cone beam computed tomography (CBCT) teeth images. Segmentation results by the proposed algorithm are then compared with the classical algorithms' results. The comparison results show that the proposed method can distinguish the root and alveolar around the root. In addition, the split molars can be segmented accurately and there are no inner contours around the pulp chamber.

Automatic detection algorithm of the diaphragm motion based on Canny edge detection and wavelet transform / 中华放射医学与防护杂志

Objective To develop a new automatic detection algorithm of the diaphragm motion based on Canny edge detection and wavelet transform.Methods On-line fluoroscopic images under free breathing were enhanced by using the wavelet transform.After the wavelet transform,edge detection was carried out for the enhanced image.Canny edge detection algorithm was used to achieve the diaphragm edge.Programs were written in Matlab to track the position of the diaphragm.The diaphragm movement curves were derived to evaluate the characteristics of patients respiratory motion.Results Under calm free breathing,the amplitude and period of diaphragm motion acquired by means of the wavelet transform and Canny edge detection were in good agreement with manual measurement.There were six to seven respiratory cycles in a XVI MotionViewTM.The magnitude of diaphragm movement was not exactly the same in the cranio-caudal (CC) direction.The magnitude was from 6.7 mm to 8.0 mm with an average of 7.4 mm.The movements of the respiratory motion cycles had little variations in amplitude and period for the same patient between fractions except emotional excitement or cough.Conclusions The automatic diaphragm detection methods developed in this paper are precise,and can effectively reflect the characteristics of the respiratory motion.The method can save much time and improve the measure precision greatly compared with the manual measurement.

Study on MITK-based Medical Image Sobel Edge Detection / 医疗卫生装备

MITK is an integrated software package for medical image process and analysis with C++ class libraries.A sobel edge detection on CT image of belly is conducted by using MITK under the VC++6.0 environment,which builds hope that the medical image process software could be developed with MITK platform.

Edge detection of medical image and methods for tracking & showing of gray level in special regions / 医疗卫生装备

By using the image processing function and programming tomography,the following functions are realized: the contour line,edge line and gradation histogram of medical images are displayed;the selected regions of medical images are freely zoomed;the gray level of discretional regions is displayed using medical image processing tool and the distance of the given points is freely measured.

A novel method using edge detection for signal extraction from cDNA microarray image analysis

Gene expression analyses by probes of hybridization from mRNA to cDNA targets arrayed on membranes or activated glass surfaces have revolutionized the way of profiling mega level gene expression. The main remaining problems however are sensitivity of detection, reproducibility and data processing. During processing of microarray images, especially irregularities of spot position and shape could generate significant errors: small regions of signal spots can be mis-included into background area and vice versa. Here we report a novel method to eliminate such obstacles by sensing their edges. Application of edge detection technology on separating spots from the background decreases the probability of the errors and gives more accurate information about the states of spots such as the pixel number, degree of fragmentation, width and height of spot, and circumference of spot. Such information can be used for the quality control of cDNA microarray experiments and filtering of low quality spots. We analyzed the cDNA microarray image that contains 10,368 genes using edge detection and compared the result with that of conventional method which draws circle around the spot.

Ring Artifact Location Algorithm Based on Edge Detection / 医疗卫生装备

Objective To investigate the Ring Artifact Location Algorithm based on edge detection to eliminate the ring artifact.Methods The Sobel operator was used to extract the ring edge,and then an algorithm,which combined scan line searching with line fitting,was applied to determining the ring center and its size.Finally the linear interpolation algorithm was used to get rid of the ring artifact.Results This method was very effective to eliminate the ring artifact of both phantom and clinical images.Conclusion This algorithm is faster and more effective than the usual one and its speed and accuracy are improved.

Image Pre-processing of Gene Chips Based on MATLAB / 医疗卫生装备

Objective To design an image pre-processing system of low-density gene chips based on MATLAB, which can process the colored images by cy3 and cy5 fluorescence staining of low-density chips obtained by the array scanning system. It can filter out noise, enhance the contrast gradient of image, improve the quality of image, and implement the functions of image segmentation, edge detection and region identification. Methods The median filter method of the wavelet was used to implement the function of image denoising and improve the image quality. Edge detection was accomplished by wavelet, combining with edge operators. Image segmentation was developed by genetic algorithms. Results It could reduce the effect of spot, noise and other factors, improve the quality of image, and detect the periphery of image better and the region of sampling point more precisely. It can also effectively separate the valuable weak signal points and background or noise with the system. Conclusion The system can accomplish the functions of image pre-processing of low-density gene chips, and the adopted methods are feasible. It can provide relative accurate data information for future analysis.

An improved method of isolation of rat cardiac myocytes / 中国药理学通报

Aim To introduce an improved method of Langendorff perfusion of the isolated rat heart that is easy to determine the termination of digestion.Methods Hearts were excised quickly from anesthetized SD rats.After the perfusate was free of blood,the solution was changed to perfusion buffer(0.6% Collagenase B,0.6% BSA,30 ?mol?L-1 Ca2+ in Tyrode solution)at 37℃.Hearts were isolated by traditional and improved Langendorff perfusion.Individual myocardial cell was measured by video-based motion edge-detection system(IonOptix,USA).Results One group of heart was digested by traditional Langendorff perfusion for 13~16 min.The termination of digestion could not be judged properly by this method.The nature and quality of the cardiocytes were various.The cardiocytes could not keep their survival and viability when exposed to Tyrode Solution with 1.8 mmol?L-1 Ca2+.Another group was digested by improved Langendorff perfusion.More than 80% survival cardiac ventricle myocytes could be obtained by improved Langendorff perfusion.Moreover,about 50% cardiac myocytes exposed to Tyrode solution with 1.8 mmol?L-1 Ca2+ could retain rod-shaped and be used to contraction research.The contraction of cardiocyte was stabile within 1 000 s.Conclusion Cardiac myocytes disassociated from improved Langendorff perfusion can be used in these studies of detecting contraction and relaxation.This method is economical and easy to control.The beginners are able to acquire the technological method over a short-term practice.